Transferring from one program to another is easIER if it's from one specialty than another. (All things being relative, that's why I put it in caps.) If it's from the same specialty, it's a hard though not impossible thing to effectuate. But you better have a very good reason! If you are in a categorical position looking to transfer home, as you say, you will eventually have to inform your current program director of your plans and why, because you need his "blessing" in order to leave and get the PGY-1 certificate showing that you have successfully completed the internship year. S/he is losing a spot that they had hoped would remain filled for the three years that you signed on for. Capitation funding, since it's paid out of the Federal Goverment's Medicare budget can be an issue if it's a small program that you want to transfer to. This, too, is not impossible, and not something for you to be concerned with. The programs have ways of working this out if they have to, and it may simply be a matter of finding the funds within the hospital's own budget to pay for the "extra" contact year if you are forced to repeat the year.
Make certain that your current rotations are well received and that you have good evals in your folder. You might also consider asking friendly attendings for a LOR for your file as you build it. Start sending out CV's as early as possible. Many programs have files where they keep this sort of data for when they have an "unexpected opening." Program directors are in communication with their peers and they generally want to keep things above board and not be perceived as "stealing" residents from other programs. Albeit rare, some places will take you without the approval of the current PG, but don't bet on it. In the course of the interview they will ask who the current program director is and if s/he has your permission to contact him/her.
Hope this is of some help in getting you started. Good luck!